At present, with the rapid popularization of network terminals, more and more network devices enters the Internet, and Internet Protocol (Internet Protocol, IP) addresses are needed for communication, which results in gradual exhaustion of Internet Protocol version 4 (IPv4) IP addresses in current use. However, an Internet Protocol version 6 (IPv6) is recognized as a core standard of the next generation Internet.
To support transition from an existing IPv4 to the IPv6, researchers have put forward multiple interworking technologies. A dual-stack (Dual-Stack) technology is the simplest, but the cost of upgrading all network infrastructures, services, applications and user terminals to dual-stack is extremely high. A tunnel technology can avoid whole network upgrading, and traversing an IPv4 network base is implemented through building an IPv6 over IPv4 tunnel between two ends of a network.
An IPv4-based IPv6 technology, such as 6to4, 6over4 and an intra-site automatic tunnel addressing protocol (Intra-Site Automatic Tunnel Addressing Protocol, ISATAP) and an IPv6 rapid deployment (6rd, IPv6 rapid deployment) technology are both methods for rapid deploying an IPv6 network in an IPv4 basic network, and in the two technologies, the IPv6 network is connected through building a stateless tunnel. In technologies such as the 6to4 and the 6rd, an Internet service provider (Internet Service Provider, ISP) may simply deploy an IPv6 gateway (6rd/6to4 border router) as a default centralized access point of the IPv6 network. A tunnel is built between a terminal or customer premises equipment (Customer Premises Equipment, CPE) and an IPv6 gateway device, an IPv6 user may traverse a network device that is not upgraded to the IPv6 and in the network through the tunnel, thereby avoiding large-scale upgrading of the network by the ISP. Therefore, the 6to4 and 6rd may assist rapid deployment of the IPv6 network.
Generally, the IPv6 network automatically configures an address and other parameters through a stateless address auto-configuration (Stateless Address Auto-configuration, SLAAC) packet and a dynamic host configuration protocol for IPv6 (Dynamic Host Configuration Protocol for IPv6, DHCPv6) packet, where SLAAC is a router advertisement (Router Advertisement) mechanism based on a neighbor discovery (Neighbor Discovery, ND) protocol.
However, in 6rd and 6to4 networks, an IPv6 packet is connected to an IPv6 gateway through a tunnel, and it is not suitable for the ND protocol and the DHCPv6 to run in the 6rd and 6to4 networks, because link broadcast needs to be used in both initial processes of the foregoing protocols. In the 6to4 technology, an IP address is usually configured manually. In the 6rd technology, both a manual manner and a DHCPv4 6rd Option manner in an IETF draft “draft-ietf-softwire-ipv6-6rd-03” may be adopted for configuration of an IP address. However, both the manual configuration and the DHCPv4 6rd Option can only configure the IP address, but cannot implement configuration of other IPv6 parameters at the same time, for example, cannot automatically obtain a default DNS server and the other IPv6 parameters.
In the prior art, although IPv6 default DNS server information and other default parameters may be commonly configured on the terminal or CPE equipment, due to the large number of terminals and CPEs, maintenance can hardly be performed through manual configuration, especially when a DNS server changes an address, all CPEs need to change configuration. In the prior art, the terminal or the CPE equipment may also directly use a default DNS of the IPv4 as a DNS server of the IPv6 network, and the terminal or the CPE equipment applies to the default DNS for a domain name through IPv4 connection. However, because the 6rd is still based on the IPv4 network, its DNS server probably does not support a request of an AAAA (an address length being four times of an IPv4 address length A) resource record (AAAA resource record).